I am using Samsung A8 plus as per DRM info my phone is having widevine L1 certification,but still I am not able to play hd videos in Amazon prime or Netflix.
may be Amazon prime or Netflix hd not compatible with your device...it's doesn't mean your device don't support hd...it's not your device fault..it's fault of compatibility with app vs system...may you notice some app or game from play store were compatible with android lollipop or kitkat version ,but same are not compatible with android oreo or pie...just like that.....developer has to fixed the issue
